Baseline Condition of Parthenium Weed at the Release sites of Biocontrol Agent/s in Wollenchiti Area of Boset District, Central Ethiopia LisaneworkNigatu and TamadoTana Haramaya University, P.O.Box 138, Dire Dawa, Ethiopia International Workshop on Parthenium Weed July 14-16, 2014, Addis Ababa, Ethiopia
Background • Invasive Alien Plant Species (IAPS) are one of the major threats to the ecological and economical wellbeing of Ethiopia. • Among the different IAPS, partheniumweed is considered to be one of the worst invasive plants in Australia, Asia and Africa • In Ethiopia, parthenium was first reported from eastern Ethiopia in the 1970sand then rapidly spread to other parts of the country
Background…….. • It has caused adverse effects on crops, on human health, on livestock health and their products, on the natural ecosystem and livelihood of people. • The obnoxious characteristics of parthenium weed can be attributed to its high seed production and effective dissemination ability, its inherent allelopathic effects on other plants, its higher phenotypic plasticity, and its ability to withstand a wide range of environmental conditions.
Background…….. • In management of parthenium, mechanical and manual methods where the plants are uprooted to prevent regeneration before flowering and when the soil is moist enough to facilitate easy removal is practiced in parts of Africa. • The use of competitive plants to suppress the growth of partheniumhas also been suggested
Background…….. • Biological control using pathogens such as the rust fungus and insects is suggested to be the most cost-effective, environmentally safe and ecologically viable method available. • Partheniumis ideal for biological control because it can continuously support biological agents because of its ability to have 4 to 7 generations per season, forms pure stands over a large area, and has many natural enemies at its center of origin • Australia and India have proved that biological control of parthenium is possible and effective. Similar work has started in South Africa to control parthenium using insects.
Background…….. • In an attempt to control the weed, biological control agent Zygogrammabicoloratawas introduced from south Africa following the standard quarantine procedure and has been evaluated under Ethiopian condition for its adaptability and host specificity at Ambo and Wolenchiti. • After passing all the necessary steps, permit was obtained from concerning government offices for its release around Wolenchiti in central Ethiopia. • Thus, it is imperative to know the baseline information on parthenium weed infestation and its effect on the livelihood of the farmers in the release sites to assess the impact of bio-control agent in the future.
Background…….. Thus, the objectives of the study were: • to assess the current above ground and soil seed bank species composition of sites invaded with parthenium weed; and • to assess the current impact of partheniumweed on the livelihood of the farmers in the release sites of the biocontrol agent
Methodology • The study area is located around Wollenchiti town, 150 km south east of Addis Ababa, in the central Rift valley in Boset district of East Shoa Zone of Oromiya Regional State, Ethiopia • The study sites fall within 1500-1600 m altitude, receive mean annual rainfall ranging between 700-900 mm with mean minimum and maximum temperatures of 18oC and 34oC, respectively.
Methodology …. • Assessment of the Above-ground Plant Community • The above-ground herbaceous plant community was sampled from three sites using five 1m x 1m quadrats at each site. • Within each of these quadrats, the plant species were identified and their density was determined by counting the number of individuals of those species present. • Moreover, their abundance was estimated by a cover percent, which involved a visual estimate of the proportion of the quadrat occupied by these species.
Methodology …. • Assessment of the Below-ground Plant Community • To assess the soil seed bank, from each of the three sites, five soil samples to a depth of 10 cm were collected at random from two opposite corners within each quadrat and mixed together to form a sample. • The soil samples were taken to the glasshouse and were spread thinly over a sterilized soil mixture in plastic pot • Two control pots, consisting of just the sterilized soil mixture, were placed among the experimental pots to monitor for any seedlings that may have arisen from this mixture contaminated them from the glasshouse environment.
Methodology …. • Assessment of the Below-ground Plant Community • The soil within the pots was watered to maintain its moisture level close to field capacity. • Pots were assessed weekly for three months for any newly emerging seedlings. • Once they emerged, seedlings were identified and counted and then removed and discarded. In the case where immediate identification was not possible, representative individuals were planted into small pots and grown to maturity, to allow for later taxonomic identification. The counted species were expressed in per m2 basis.
Methodology …. • Assessment of Socio-economic Impact of Partheniumweed • The study was conducted at three release sites, i.e. Borcheta, Tedecha and Tribret around Wollenchiti town • At each site representative farmers were selected and interviewed using structured questionnaire. • Major data collected include awareness about parthenium, means of its introduction, status of its infestation, its effects on crops, native species, human and animal health and produce and control method used. • The responses of the framers were summarized using percentages
RESULTS • The Above-ground Species Abundance • The highest cover percentage (68.8%), density (465 plants m-2) and plant height (30.4 cm) of parthenium weed at Borcheta site followed by Tedechasite. On the other hand, plots at Boset Secondary School had the lowest parthenium weed cover percentage, density and height.
RESULTS…. • The Soil Seed bank Composition and Size • From the soil seed bank study, a total of 24 species belonging to 14 plant families were recorded. The most frequent families based on the number of species were Poaceae (7) and Asteraceae (4). • Annuals were more common (20 taxa) than perennials (4 taxa) • The highest density of parthenium (2065.6 plants m-2) was recorded in the soil seed bank at Borcheta • Unlike on the aboveground vegetation, the density of parthenium in the soil seed bank was high at Boset Secondary School indicating the high persistence of parthenium weed seeds in the soil.
Cover percent of parthenium weed and reduction in carrying capacity of grazing land
Conclusion • Parthenium weed has enormous seed bank and above ground cover percent in the study area • Its infestation of has significantly reduced the amount and composition of both the above ground and the seed bank of herbaceous vegetation and negatively affected the livelihood of farmers in the study area.
Conclusion….. • Farmers are aware ofparthenium, its distribution and means of dissemination, and its negative impact on their wellbeing, crop and livestock production. • They are also making some efforts to limit the spread of parthenium. However, the success in controlling the spread of parthenium is limited because of the abundance of parthenium seed in the seed bank, its ability to grow fast, weeding after seed setting, not uprooting or uprooting was not done at the appropriate time, and lack of coordinated effort.
Conclusion….. • No mich effort is made to control the weed in non-cultivated lands such as grazing areas, wastelands, roadsides, etc except some campaigns which are not done in coordinated and continuous manner. • Thus, integrated management programs must be carried out to control parthenium weed. Biological control of partheniumcan be an ideal option especially in uncultivated lands • In general, coordinated and concerted efforts must be made by the local people, extension staff, researchers, governments and non-government organizations to mange parthenium weed.
ACKNOWLEDGMENTS • USAID through IPM/CRSP for financial support • Haramaya University for providing vehicle and facilities • Students Tujare Shore and MedhanitBekele for field work